Quaternized and boronic acid dual-functional CoAg nanozymes for label-free, stable, sensitive, and rapid quantitation detection of the bacterial total concentration.

BACKGROUND: Foodborne pathogenic bacteria lead to a significant increase in illnesses and fatalities annually. In the early stage of a pathogenic bacterial infection, the concentration of bacteria in food is lower than the detection limit of most technology which enhances the difficulty in diagnosis. It is a serious challenge for researchers to develop a rapid, sensitive, accurate, and stable pathogenic bacterial determination method without costly equipment and highly skilled operators.

RESULTS: It is clear that the bacterial total concentration in food increased obviously could be attributed to microbial contamination in food. Herein, quaternized and boronic acid dual-functional capped CoAg nanozymes, known as CoAg@HTCC-B, were developed and synthesized to exhibit strong and stable chemiluminescence (CL) emission to detect bacterial total concentrations. The CoAg@HTCC-B nanozymes are capable of accurately quantifying the total concentrations of a mixed bacterial solution (S. aureus and E. coli) over a broad detection range and with a low limit of detection (LOD). These nanozymes were utilized for the detection of E. coli or S. aureus in fresh chicken samples with LOD values of 2.08 colony-forming units per milliliter (CFU/mL) for E. coli and 1.71 CFU/mL for S. aureus.

SIGNIFICANCE: This suggests that the CoAg@HTCC-B nanozymes have the potential for early-stage monitoring of microbial contamination in meat samples. The capability of CoAg@HTCC-B nanozymes in swiftly and accurately detecting known bacterial concentrations suggested their potential as a viable alternative to the traditional culture-based approach for quantitatively determining known bacterial concentrations in academic, research, or industrial settings.